This invention relates to the preparation of microspheres from acrylates and methacrylates, which microspheres have improved adhesive properties.
U.S. Pat. No. 3,720,534, which is hereby fully incorporated by reference, teaches a method of acrylate gel formation by a suspension polymerization. The polymeric microparticles have occluded in situ about 35-80% by weight of a non-volatile, non-drying oil.
Although acrylate polymers are well-known for their intrinsic adhesive properties, the microparticles prepared according to U.S. Pat. No. 3,720,534 do not have good adhesive properties, because the polymers have too high a glass transition temperature and also the microparticles contain too much oil inside the particles.
It is known prior art that a tacky adhesive may be produced by polymerizing an acrylate or methacrylate. Such polymers can be deposited on bond paper and used as pressure sensitive adhesive. While the use of acrylates and methacrylates in general to form adhesives are known, it would nevertheless be advantageous to vary the level of tack. If such variations in tack level could be achieved it would be possible to produce an adhesive having an appropriate tack level required in a specific application.